Masterful Replication copies the printed values of the target artifact. It won’t copy counters on that artifact or effects that have changed its power, toughness, types, color, or so on. Notably, it won’t copy effects that made the target artifact become an artifact creature if it isn’t normally an artifact creature.

7/12/2019

An Equipment that becomes a copy of a creature becomes unattached if it was attached to a creature. An Equipment that becomes a copy of another Equipment remains attached if it was attached to a creature.

7/12/2019

If the target artifact is copying something else, then your artifacts become copies of whatever the target artifact copied.